In a Fifth Generation mobile communication network New Radio (5GNR) system, a carrier may be corresponding to a plurality of numerologies. Each numerology may include a Sub-Carrier Spacing (SCS) and Cyclic Prefix (CP) length. Therefore, in the 5GNR system, the carrier has a flexible configuration, which allows different application scenarios to be applied within the carrier, such as Enhanced Mobile Broad Band (EMBB) and Ultra Reliable and Low Latency Communication (URLLC), and the carrier is especially adapted for application in network slicing. However, this also brings challenge in transmission of a synchronization signal and a physical broadcast channel (referred to as a broadcast channel hereinafter).
When initially accessing a network, a user equipment (UE) needs to detect the synchronization signal and the downlink control channel, since there is no priori information on a numerology of the synchronization signal and a numerology of the downlink control channel, a blind detection is required potentially. In a Long Term Evolution (LTE) system, the UE needs to blindly detect whether a Normal Cyclic Prefix (NCP) or an Extended Cyclic Prefix (ECP) is used at the initial access. However, in the 5GNR system, there are plenty of possibilities of subcarrier spacing and CP length in the numerologies so as to support flexibility, therefore the blind detection is of high complexity.
Take the synchronization signal for example, in order to reduce the complexity of blind detection, one approach is to preset an SCS of the synchronization signal, and then send a synchronization signal with a fixed numerology on the carrier.
However, when information is transmitted to the UE as described above, the carrier applied to mapping is confined to a carrier using a same numerology as the synchronization signal with the fixed numerology. How to transmit the synchronization signal and the broadcast channel to the UE using a carrier of a non-fixed numerology has become a key problem to be solved.